CN110913933A

CN110913933A - Dispensing system for cryogenic skin treatment

Info

Publication number: CN110913933A
Application number: CN201880045996.4A
Authority: CN
Inventors: D·H·P·克莱尔; H·C·佩利卡恩
Original assignee: Dutch Renewable Energy Co
Current assignee: Dutch Renewable Energy Co
Priority date: 2017-07-19
Filing date: 2018-07-13
Publication date: 2020-03-24
Anticipated expiration: 2038-07-13
Also published as: EP3655074B1; US20200146739A1; BR112020001098A2; AU2018304851A1; US11564726B2; WO2019016105A1; CN110913933B; EP3655074A1; KR20200031617A; BR112020001098B1; CA3068911A1; ES2884906T3

Abstract

The present invention relates to a dispensing system for cryogenic skin treatment that enables targeted delivery of a cryogen at a high rate to achieve rapid freezing of targeted skin tissue. The distribution system of the present invention uses a refrigerant comprising dimethyl ether and is designed to deliver the refrigerant in an accurate and very efficient manner.

Description

Dispensing system for cryogenic skin treatment

Technical Field

The present invention relates to a dispensing system for cryogenic skin treatment. The distribution system of the present invention comprises:

a container containing a cryogen;

an actuatable valve comprising a chamber and a nozzle connected to an outlet of the chamber;

a spacer attached to the container or the valve, the spacer being adapted to define a predetermined distance between the orifice of the nozzle and a skin surface to be treated.

The dispensing system of the present invention may suitably be used to improve the appearance of skin by treating warts, moles, freckles, skin tags, age spots, lentigo or other skin related abnormalities. Thus, the present invention also relates to a cosmetic method of treating the skin, said method comprising the topical application of a cryogenic dispersion onto the skin of a human or animal using the above-described dispensing system.

Background

Skin treatments that improve the appearance of skin are widely used. Skin conditions commonly targeted by such treatments include warts, moles, freckles, skin tags, age spots (also known as liver spots), lentigo, or other skin-related abnormalities.

There are several methods of treating these skin conditions, ranging from topical improvement to more aggressive treatments, such as laser treatment or cryotherapy. Topical treatments include lotions, creams, acids, bleaches, and vitamins. However, such treatments are often slow, result in subtle improvements in the skin, may cause low or high pigmentation, and are often inadequate.

In order to provide a more complete treatment of the skin, it is known to use laser therapy. However, laser treatment can result in unnecessary pain and extensive scarring.

Cryogenic treatments are also known in the art, and such treatments typically involve the application of liquid nitrogen or another cryogen directly to a portion of the skin. This method is often used because of its effectiveness and limited side effects.

When using low temperature processing, it is important to cool the processing region to an appropriate temperature for an appropriate time. Cooling the zone to too low a temperature can result in excessive damage. Cooling the area too long will induce a warm conduction of the cold to the adjacent tissue, thereby increasing the size of the affected area. Furthermore, although the surrounding tissue can survive brief exposure to very low temperatures, prolonged exposure can lead to tissue necrosis or excessive damage.

US5516505 describes a method of cryogenically treating a skin surface lesion, the method comprising the steps of:

releasing the cryogenic agent from the aerosol or pressurized container, allowing the cryogenic agent to accumulate in the synthetic plastic foam applicator,

contacting the diseased skin surface with a synthetic plastic foam applicator having an accumulated cryogenic agent for a period of time sufficient to freeze the skin tissue such that permanent, irreversible rupture of cell membranes of the skin diseased cells occurs upon vaporization of the cryo-volume,

the synthetic plastic foam applicator is subsequently removed from the skin surface, an

Thereafter, the frozen skin tissue of the skin lesion is slowly thawed.

Us5125546 describes an aerosol discharge valve assembly for regulating the flow of a liquid product from an aerosol container substantially pressurised by a permanent propellant gas, said assembly comprising:

(a) a control valve mounted on the vessel;

(b) an outlet nozzle;

(c) a tubular member projecting upwardly and outwardly from the container and defining a passage covered by the outlet nozzle through which the atomized mixture of propellant gas and liquid product can flow out of the container;

(d) a tubular member projecting downwardly in the container, the control valve being operable between open and closed positions to control flow through the control valve and the tubular member;

(e) first passage means for conveying liquid under gas pressure into said downwardly projecting tubular member for delivery to a mixing region in said valve assembly;

(f) second passage means downstream of said first passage means for conveying pressurised gas to said downwardly projecting tubular member separately from liquid product for delivery to said mixing zone;

(g) at least one intermediate throttle between the mixing zone and the outlet nozzle, through which throttle the mixture of liquid product and pressurised gas is forced; and

(H) the dimensions of the throttle valve relative to the first and second passage means are selected to provide an at least substantially sonic choked flow through the throttle valve at and above a selected minimum internal gas pressure, the mixed liquid product and propellant gas passing through the throttle valve such that the liquid product breaks up into fine droplets comprising a highly dispersed foamed liquid product in response to a change from subsonic to sonic flow and back to subsonic flow.

US2004/102768 describes a cryotherapeutic device adapted to be operated with one hand, using the expansion temperature and pressure of a liquefied gas sprayed in at least a part solid phase onto the epidermis of a human or animal, which is contained under pressure in a movable cartridge, wherein the holder of the cartridge and a controlled spraying and expansion system are arranged substantially linearly along the axis of the device in an ergonomic housing, the axis of which corresponds to the axis of the device, the middle part of which serves as a handle for the adult user's hand to grasp, and comprises a member for controlling the controlled gas spraying and expansion system, the upper part of which has an inlet for introducing the cartridge into its holder down and along the housing axis and, after use, striking or withdrawing it, and the lower part of which comprises a calibrated opening forming a passage for the gas spray substantially along the housing axis, and means for maintaining the outlet nozzle of the controlled spray and expansion system at a desired distance relative to the epidermal area to be treated.

WO2016/010428 describes a spray for topical application of liquids and/or solids to a surface comprising:

a container designed to contain the colloidal substance and the medium;

a manipulable valve mounted on said container; and

a nozzle mounted on the valve for generating a stream or spray of water,

wherein the valve:

comprising a mixing chamber attached to the nozzle; and

comprising a first and a second inlet attached to the mixing chamber for delivering the colloidal substance and the medium, respectively, to the mixing chamber,

wherein the mixing chamber is designed for forming a colloidal mixture comprising the colloidal substance and a medium and then for delivering the colloidal mixture to the nozzle, characterized in that the colloidal mixture comprises a dispersed phase consisting of a liquid and/or solid substance and a continuous phase consisting of a propellant gas.

Disclosure of Invention

The inventors have developed a dispensing system for frozen skin treatments that enables targeted delivery of a cryogen at a high rate to achieve rapid freezing of targeted skin tissue. The distribution system of the present invention uses a refrigerant comprising dimethyl ether and is designed to deliver the refrigerant in an accurate and very efficient manner.

The dispensing device of the present invention comprises:

a vessel comprising a liquid phase in direct contact with and in equilibrium with a gaseous phase at a pressure of from 2.5 to 8 bar, the liquid phase comprising liquefied dimethyl ether;

an actuatable valve attached to the container, the valve comprising:

a mixing chamber comprising an inlet and an outlet, wherein the inlet comprises a venturi tube having an inlet cone for receiving a gas phase from the vessel, an outlet cone and a constriction section connecting the inlet cone with the outlet cone, the constriction section or the outlet cone comprising a liquid inlet for receiving a liquid phase from the vessel;

a nozzle connected to the outlet of the mixing chamber;

a barrier attached to the container or the valve, the barrier adapted to define a predetermined distance between the orifice of the nozzle and a skin surface to be treated; the far end of the isolating piece is provided with a spray opening;

wherein the dispensing system is arranged to be used in an inverted position, wherein the distal end of the barrier is placed in direct contact with the skin surface to be treated and the nozzle is positioned below the container; and wherein, during such inverted use, upon actuation of the valve:

the gas phase enters the mixing chamber through the venturi tube, creating a venturi effect capable of causing: (i) drawing a liquid phase into the outlet cone of the venturi through the liquid inlet, and (ii) dispersing the liquid phase into a gas phase; and is

The resulting low temperature liquid-in-air dispersion is discharged through the orifice of the nozzle and through the spray opening of the barrier, thereby delivering the low temperature dispersion to the skin surface.

The dispensing device of the present invention is designed to provide very accurate delivery of the cryogenic dispersion at very high rates. Thus, the dispensing device can effectively treat skin abnormalities with minimal damage to the surrounding skin tissue.

The present invention also provides a cosmetic method of treating skin comprising topically applying a cryogenic dispersion to the skin of a human or animal using the dispensing system described above.

Accordingly, a first aspect of the invention relates to a dispensing system for cryogenic skin treatment, the system comprising:

a vessel having an internal volume of from 10 to 200ml, said vessel comprising a liquid phase in direct contact with and in equilibrium with a vapour phase at a pressure of from 2.5 to 8 bar, said liquid phase comprising at least 50 wt% liquefied dimethyl ether;

an actuatable valve attached to the container, the valve comprising:

a mixing chamber having an internal working volume of 10-600 μ l and comprising an inlet and an outlet, wherein the inlet comprises a venturi tube having an inlet cone for receiving a gas phase from the vessel, an outlet cone and a converging section connecting the inlet cone and the outlet cone, the converging section or the outlet cone comprising a liquid inlet for receiving a liquid phase from the vessel, the liquid inlet having a cross-sectional opening area of 8x10-3 to 100x10-3mm2 and the converging section having a cross-sectional opening area at least 150% larger than the cross-sectional opening area of the liquid inlet;

a nozzle connected to the outlet of the mixing chamber, the nozzle comprising an orifice having a cross-sectional opening area in the range of 8x10 "3 to 100x 10" 3mm 2;

a barrier attached to the container or the valve, the barrier adapted to define a predetermined distance between the orifice of the nozzle and a skin surface to be treated; a distal end of the spacer is provided with a spray opening, the distance between the spray opening and the orifice of the nozzle being in the range of 2 to 25 mm;

wherein the dispensing system is arranged to be used in an inverted position, wherein the distal end of the barrier is placed in direct contact with the skin surrounding the skin surface to be treated, and the nozzle is positioned below the container; and wherein, during such inverted use, upon actuation of the valve:

the gas phase enters the mixing chamber through the venturi tube, creating a venturi effect capable of causing: (i) drawing the liquid phase into the venturi through the liquid inlet, and (ii) dispersing the liquid phase into the gas phase; and is

The resulting cryogenic liquid-in-air dispersion is discharged through the orifice of the nozzle and through the spray opening of the barrier to deliver the cryogenic dispersion to the skin surface to be treated at a rate of 30-200 mg/s.

The dispensing system of the present invention is arranged for use in an inverted position with the nozzle below the container. In this inverted position, the majority of the liquid phase in the vessel is located above the nozzle.

As used herein, the term "cross-sectional openingArea "refers to the smallest cross-sectional area of a hole or conduit, perpendicular to the main flow through the hole or conduit. In the case of a spherical opening, the cross-sectional opening area is equal to π r²Where r is the radius of the spherical opening.

The present invention includes embodiments of a dispensing system in which the volume of the mixing chamber changes upon actuation of the actuatable valve. The term "working volume" refers to the volume of the mixing chamber when the valve is fully actuated.

The pressure at which the liquid and gaseous phases were contained in the vessel was determined to be 20 ℃.

The rate of delivery of the cryogenic dispersion to the skin surface by the present dispensing device was determined at 20 ℃ and atmospheric pressure.

The requirement that the cross-sectional opening area of the constriction is at least 150% larger than the cross-sectional opening area of the liquid inlet means that if the cross-sectional opening area of the liquid inlet is 0.12mm²The cross section must have at least 0.3mm²Cross-sectional open area of.

The internal volume of the container is generally from 20 to 150ml, more particularly from 25 to 120 ml.

The liquid and gaseous phases are preferably present in the vessel at a pressure of 3-7 bar.

The inlet cone of the venturi is connected to a suction tube that extends into the container. The maximum diameter of the inlet cone is preferably at least 0.6mm, more preferably 0.6 to 3 mm. The suction tube typically does not extend until near the distal end of the container. More particularly, it is preferred that the suction tube does not extend into the liquid phase within the container when the dispensing system is in the fill position and the nozzle is positioned above the container throughout the life cycle of the dispensing system. Thus, when the valve is actuated in the fill position, no cryogenic dispersion is released from the dispensing system. However, when the valve is actuated in an inverted position, the gas phase enters the mixing chamber through the venturi tube, and if there is still sufficient liquid phase in the container to feed into the liquid inlet, the venturi effect will draw the liquid phase into the venturi tube through the liquid inlet. The venturi effect also results in the dispersion of the liquid phase into the gas phase under the formation of a low temperature dispersion.

The cross-sectional open area of the suction tube is preferably at least 70% greater, more preferably at least 130% greater than the cross-sectional open area of the converging section of the venturi.

According to another preferred embodiment, the liquid inlet of the venturi connects a constriction or outlet cone of the venturi with the interior of the vessel adjacent to the valve.

The liquid inlet is preferably located in the exit cone of the venturi.

The constriction of the venturi tube typically has a diameter of 0.12-0.50mm²More preferably 0.16-0.44mm²Most preferably 0.20-0.38mm²。

The venturi preferably has an inlet cone of 30-90 degrees, more preferably 35-80 degrees, most preferably 40-70 degrees.

The venturi preferably has an exit cone of 10-40 degrees, more preferably 15-35 degrees, most preferably 20-32 degrees.

According to a particularly preferred embodiment, the cone angle of the inlet cone is at least 30%, preferably at least 50%, most preferably at least 70% greater than the cone angle of the outlet cone. The requirement that the inlet cone is at least 70% larger with an outlet cone of 28 degrees means that the inlet cone should be at least 47.6 degrees.

The cross-sectional opening area of the liquid inlet is preferably 18 x10^-3To 72X 10^-3mm²More preferably 25X 10^-3To 62X 10^-3mm²。

The cross-sectional opening area of the converging section of the venturi is preferably at least 200%, more preferably 300-800% larger than the cross-sectional opening area of the liquid inlet.

The mixing chamber preferably has an internal working volume of 20-500. mu.l, more preferably 40-400. mu.l.

The cross-sectional opening area of the nozzle orifice is preferably 11X 10^-3To 72X 10^-3mm²More preferably 13X 10, in the range of^-3 To 50X 10^-3mm²Most preferably in the range of 15X 10^-3To 35X 10^-3mm²Within the range of (1).

The low temperature dispersion is typically discharged through the orifice of a nozzle forming a spray cone with an angle of no more than 40 degrees, more preferably no more than 30 degrees and most preferably no more than 20 degrees.

In addition to dimethyl ether, the liquid phase may also contain other components such as propellants other than dimethyl ether, keratolytic agents (e.g. glycolic acid or salicylic acid), emollients, antioxidants, trichloroacetic acid, dichloroacetic acid, monochloroacetic acid and co-solvents.

In one embodiment of the invention, the liquid phase comprises at least 90 wt.% dimethyl ether. More preferably, the liquid phase consists of dimethyl ether and is in equilibrium with a gas phase which also consists of dimethyl ether.

In another embodiment, the liquid phase comprises at least 90 wt.%, more preferably at least 95 wt.% of a mixture of dimethyl ether and one or more alkanes selected from propane, n-butane and isobutane. More preferably, the liquid and vapour phases consist of a mixture of dimethyl ether and the one or more alkanes.

The liquid phase preferably comprises at least 90 wt.%, more preferably at least 95 wt.% of a mixture of dimethyl ether and propane. More preferably, the liquid and vapor phases consist of a mixture of dimethyl ether and propane.

According to a particularly preferred embodiment, the mixture of dimethyl ether and one or more alkanes comprises in a weight ratio of 1: 1 to 9: 1, more preferably 3: 2 to 5: 1, preferably 2: 1 to 4: 1 and one or more alkanes.

Preferably, the distance between the orifice of the nozzle and the spray opening of the partition is in the range of 4 to 22mm, more preferably in the range of 8 to 20mm, most preferably in the range of 10 to 18 mm.

The minimum diameter of the spray opening of the spacer is preferably 2-10mm, more preferably 3-9mm, most preferably 4-8 mm.

The minimum and maximum diameters of the spray openings of the spacers are preferably of the same order of magnitude. Typically, the aspect ratio of the spray opening is less than 2: 1, more preferably less than 1.5: 1, and most preferably less than 1.2: 1.

The partition preferably comprises a solid member defining an internal chamber forming a spray conduit and having a spray opening at its distal end.

The solid element of the spacer preferably comprises at least one opening. The at least one opening facilitates evaporation of the cryogenic suspension once the cryogenic suspension is sprayed onto the skin surface. In addition, the at least one opening allows the user to verify whether the cryogenic dispersion is adequately delivered to the skin surface.

The dispensing system is preferably arranged such that the distance between the spray opening and the nozzle orifice does not change upon actuation of the valve. This may advantageously be achieved by attaching the spacer to the valve.

In a particularly preferred embodiment, the actuatable valve comprises a fixed portion fixed to the vessel and comprising the venturi and the liquid inlet and forming a circumferential sidewall of the mixing chamber, the valve further comprising a movable portion movable relative to the fixed portion between a valve open position and a valve closed position, the movable portion comprising a nozzle, wherein the nozzle has a circumferential sidewall surrounding the passage for the liquid-in-gas dispersion and a through hole in the sidewall, wherein the through hole is arranged such that: in the valve open position, the through hole fluidly connects the mixing chamber and the orifice of the nozzle, and in the valve closed position, the movable part and the stationary part together seal a passage between the mixing chamber and the through hole.

According to a more preferred embodiment, the stationary part is provided with a gasket through which the movable part extends, wherein the gasket seals the passage between the mixing chamber and the through hole when the movable part is in the valve closed position.

In a further preferred embodiment of the present dispensing system, the container has a top wall at an end opposite the nozzle, the system further comprising a holder for movably holding the container therein, wherein the partition and the nozzle are fixed relative to the holder, and the holder surrounds a substantial portion of a circumferential outer wall of the container while leaving the top wall at least partially free to allow a user to actuate the valve relative to the container towards the spray opening by pressing his or her finger on the top wall of the container. An advantage of this embodiment is that the dispensing system can be operated with one hand.

The spray opening in the barrier preferably extends through a contact surface of the barrier, which contact surface is adapted to be in contact with skin surrounding the skin to be treated, wherein said contact surface extends substantially perpendicular to the spray direction of the orifice of the nozzle.

The spray opening is preferably surrounded by a covering means comprising an edge, preferably a circumferential edge, which prevents the cryogenic dispersion from being applied to the skin other than through the spray opening.

Upon valve actuation, the cryogenic dispersion is preferably delivered to the skin surface at a rate of 35-120mg/s, most preferably 40-100 mg/s.

An alternative embodiment of the invention relates to a dispensing apparatus as described above except that 1,1,1, 2-tetrafluoroethane is used instead of dimethyl ether. In other words, according to this embodiment, the liquid phase in the vessel comprises 1,1,1, 2-tetrafluoroethane.

Preferably, according to this alternative embodiment, the liquid phase comprises at least 50% by weight, more preferably at least 80% by weight, most preferably at least 1,1,1, 2-tetrafluoroethane.

Yet another alternative embodiment of the present invention is directed to a dispensing apparatus as described above except that 2,3,3, 3-tetrafluoropropene is used instead of dimethyl ether. In other words, according to this embodiment, the liquid phase in the vessel comprises 2,3,3, 3-tetrafluoropropene.

Preferably, according to this alternative embodiment, the liquid phase comprises at least 50 wt.%, more preferably at least 80 wt.%, most preferably at least 2,3,3, 3-tetrafluoropropene.

Another aspect of the invention relates to a cosmetic method of treating skin comprising topically applying a cryogenic dispersion to the skin of a human or animal using the dispensing system described herein.

According to a preferred embodiment of the method, the cryogenic dispersion is applied to warts, moles, freckles, skin tags, age spots or lentigo. Most preferably, the low temperature dispersion is applied to the warts.

Typically, the cryogenic dispersion is continuously delivered to the skin using a dispensing system over a period of 2 to 30 seconds, more preferably 4 to 20 seconds.

Drawings

The invention is further explained below with reference to the drawings, in which:

fig. 1A, 1B, 1C, 1D, 1E schematically show a cross-sectional view of a dispensing system according to the invention and details thereof;

fig. 2A, 2B, 2C show a representation of a dispensing system according to the invention provided with a holder around the container.

Detailed Description

Fig. 1A and 1B respectively show a dispensing system 1 according to the invention, wherein the actuatable valve 20 is closed, thereby preventing fluid and gas from the interior of the container from flowing out of the container 10 through the nozzle 30, and the nozzle 30 is in fluid communication with the interior of the container 10 with the valve 20 open. Although in the illustrated embodiment the nozzle 30 comprises two

parts

32, 33 connected to each other, it will be appreciated that the nozzle may also be formed as a single unit.

The container has an internal volume of about 120ml for containing the liquid phase 11 and the gas phase 12 in direct contact with each other. In the embodiment shown, both the liquid phase and the gaseous phase are at a pressure of about 4bar, the liquid phase 11 consisting of liquefied dimethyl ether. Alternatively, the liquid phase 11 may consist of a 3: 1(w/w) mixture of liquefied dimethyl ether and liquefied propane.

The nozzle 30 of the valve 20 is attached to the container 10. The spacer 40 is fixed to the container and ensures that the orifice 31 of the nozzle 30 remains spaced from the spray opening 41 of the spacer 40. The orifice 31 of the nozzle 30 has a relatively small cross-sectional opening area in the range of 0.018-0.07mm2 through which a directed spray of the aerosol-liquid dispersion 50 can be directed toward the opening 41 of the partition, which opening 41 has a larger cross-sectional opening area in a plane perpendicular to the longitudinal direction of the nozzle. During use, for example when cryogenically treating warts, the dispensing system is positioned so that the contact surface 48 of the barrier member contacts the skin surrounding the area of skin to be treated and so that the skin 80 to be treated is accessible through the opening 41. The viewing port 46 in the side wall 47 of the barrier member allows the skin to be treated to be viewed from the side of the barrier member facing away from the contact surface 48, thereby facilitating the positioning of the dispensing device and the inspection of the skin during treatment. The viewing port preferably comprises an opening in the sidewall 47 so that condensate from the dispersion of the aerosol can exit the barrier without having to remove the barrier from the skin and without obstructing the view of the skin to be treated.

The valve 20 comprises a fixed portion 18 fixed to the container 10 and a movable portion 19 movable relative to the container between a valve closed position shown in figure 1A and a valve open position shown in figure 1B. Fig. 1C shows the valve 20 in a valve open position in more detail, but the spacer 40 is not shown for clarity. The movable part 19 and the stationary part 18 together form a mixing chamber 21, the mixing chamber 21 having an inlet 22 for supplying the liquid phase 11 and the phase 12 to the mixing chamber. The volume of the mixing chamber 21 depends on the position of the movable part 19 relative to the fixed part and has a volume of about 200 μ l when the valve is fully actuated to the valve open position. In order to receive the gas phase 12 from the vessel, the inlet is provided with a venturi tube 24, the venturi tube 24 having an inlet cone 25, the inlet cone 25 in turn being connected to a suction tube 29 extending into the vessel. The venturi tube 24 tapers towards a converging section 26 connected thereto, which converging section 26 is in turn connected to a separate outlet cone 27 in the mixing chamber 21. The constriction 26 further comprises a liquid inlet 28 for receiving the liquid phase 11. When the device is in the inverted position and the movable part 19 is in the valve-open position, as shown in fig. 1B and 1C, the propellant gas 12 flows through the venturi tube 24, creating a negative pressure in the liquid inlet 28, as a result of which the liquid 11 is sucked into the mixing chamber 21 together with the propellant gas 12, the two phases further mixing to form a liquid-in-gas dispersion. Referring also to fig. 1B, the liquid-in-gas dispersion 50 is ejected from the mixing chamber 21 through the through-hole 15 in the sidewall 16 of the nozzle 30 and out of the nozzle orifice 31 into the spray opening 41. The movable portion 19 may remain in the valve open position for any desired amount of time, for example, until the pressure within the container is substantially equal to the pressure outside the dispenser system.

Fig. 1D schematically shows a cross-sectional isometric view of a portion of the dispensing system with the movable portion 19 in a valve-open position showing how the dispersion in gas-in-liquid travels from the mixing chamber 21 to the outlet 23 of the mixing chamber along the recess 14 on the inner periphery of the fixed portion 18.

Referring to fig. 1D as well as fig. 1A, when the movable portion 19 is in the valve-closed position, the fluid communication between the mixing chamber 21 and the interior of the vessel 10 containing the gas phase 12 and the liquid phase 11 remains open. However, the fluid communication from the mixing chamber 21 to the nozzle 30 via the opening 15 is sealed by the gasket 60, the nozzle 30 extends through the gasket 60, and the gasket 60 sealingly abuts against a shoulder 63 of the stationary part 18, which shoulder 63 is abutted against the gasket 60 by the spring 64. Thus, gasket 60 is compressed between shoulder 63 of movable portion 19 and bottom wall 62 of container 10. A further gasket 61 is attached to the active portion 19 to prevent gases and/or liquids from escaping from the container 64 along the outer surface of the active portion.

Figure 1E shows a detail of the nozzle 30 and a portion of the barrier 40. the nozzle orifice 31 has a relatively small diameter d1 of between 0.15-0.30mm to ensure that the liquid dispersion in air-bag 50 is ejected from the orifice 31 in a narrow spray cone-like angle α of the spray cone is about 30 degrees the contact surface 48 of the barrier 40 is in contact with the skin portion 80 while keeping the skin to be treated free, thus the liquid dispersion in air-bag 50 can reach the portion of the skin to be treated that is located below the spray opening 41. the fixed distance h1 between the spray opening 41 and the orifice 31 is between 2 and 25mm, regardless of whether the valve is in the valve open or valve closed position.

Fig. 2A, 2B and 2C show a schematic cross-sectional side view, a side view and an isometric view, respectively, of a dispensing system according to the invention, further comprising a holder 70 for holding the container therein such that the container 10 is movable relative to the holder in the longitudinal direction L of both. Although the container 10 typically comprises metal, the holder may be made of a plastic that is more flexible than the container. During use, the position of the retainer 70 relative to the nozzle 30 and the barrier 40 is fixed regardless of whether the valve is open or closed. The spacer 40 is attached to the holder 70 at a bottom side 71 of the holder 70, while the holder 70 releases a portion of the top wall 9 of the container 10 opposite the bottom wall 62 of the container 10 at its opposite top side 72. When the partition 40 is in contact with the skin to be treated, the user can press the top wall 9 of the container 10 downwards with respect to the holder 70 and towards the spray opening 41, for example by pressing his finger or thumb on the top wall 9, in such a way as to move the active portion 19 of the actuator valve 20 to the valve-open position.

As can be seen more clearly in FIG. 2A, the length L1 of container 10 is less than the sum of the lengths L2 of retainer 70 and spacer 40. More particularly, the holder 70 extends a length greater than the length of the container 10 held therein. The holder 70 is provided with an opening 74 near its top side 72 through which the container 10 can be inserted into the holder 70 or removed from the holder 70. The opening 74 has an edge 73, which edge 73 overlaps a portion of the top wall 9 of the container 10 when projected onto the top wall 9 of the container 10 on a plane perpendicular to the longitudinal direction of the container 10. The rim 73 thus helps prevent the container 10 from accidentally falling out of the holder 70. When the gas and/or liquid phase in the vessel 10 is exhausted, the vessel 10 may be removed from the holder 70 and then replaced with another vessel.

Claims

1. A dispensing system (1) for cryogenic skin treatment, the system (1) comprising:

a vessel (10) having an internal volume of 10-200ml, said vessel comprising a liquid phase (11) in direct contact with and in equilibrium with a gaseous phase (12) at a pressure of 2.5-8 bar, said liquid phase (11) comprising at least 50 wt.% liquefied dimethyl ether;

an actuatable valve (20), the actuatable valve (20) attached to the container (10), the valve comprising:

a mixing chamber (21) having an internal working volume of 10-600 μ l and comprising an inlet (22) and an outlet (23), wherein the inlet comprises a venturi tube (24) having an inlet cone (25), an outlet cone (27) and a converging section (26) connecting the inlet cone (25) and the outlet cone (27), the inlet cone (25) being adapted to receive a gas phase (12) from the vessel (10), the converging section (26) or the outlet cone (27) comprising a liquid inlet (28) adapted to receive a liquid phase (11) from the vessel (10), the liquid inlet (28) having a cross-sectional opening area of 8x10^-3To 100x10^-3mm²And the cross-sectional opening area of the constriction section (26) is at least greater than that of the liquid inlet (28)The cross section opening area is 150 percent;

a nozzle (30), the nozzle (30) being connected to the outlet of the mixing chamber, the nozzle (30) comprising an orifice (31) having a cross-sectional opening area of 8x10^-3To 100X10^-3mm²Within the range of (1);

a spacer (40) attached to the container (10) or the valve (20), the spacer (40) being adapted to define a predetermined distance between the orifice (31) of the nozzle (30) and a skin surface to be treated; -the distal end of the partition (40) is provided with a spray opening (41), the distance (h1) between the spray opening (41) and the orifice (31) of the nozzle (30) being in the range of 2 to 25 mm;

wherein the dispensing system (1) is arranged to be used in an inverted position, wherein the distal end of the barrier (40) is placed in direct contact with the skin surrounding the skin surface to be treated, and the nozzle (30) is positioned below the container (10); and wherein, during such inverted use, upon actuation of the valve (20):

the gaseous phase (12) enters the mixing chamber (21) through the venturi tube (24), creating a venturi effect capable of causing: (i) drawing the liquid phase (11) into the venturi tube (24) through the liquid inlet (28), and (ii) dispersing the liquid phase (11) into the gas phase (12); and is

The resulting low temperature liquid-in-air dispersion (50) is discharged through the orifice (31) of the nozzle (30) and through the spray opening (41) of the barrier (40) to deliver the low temperature dispersion (50) to the skin surface to be treated at a rate of 30-200 mg/s.

2. Dispensing system according to claim 1, wherein the inlet cone (25) of the venturi tube (24) is connected to a suction tube (29), the suction tube (29) extending into the container (10).

3. Dispensing system according to claim 1 or 2, wherein the liquid inlet (28) of the venturi tube (24) connects a constriction (26) or an outlet cone (27) of the venturi tube (24) with an interior of the container (10) adjacent to the valve (20).

4. Dispensing system according to any one of the preceding claims, wherein the constriction section (26) of the venturi tube (24) has a diameter of 0.12 to 0.5mm²Cross-sectional open area of.

5. The dispensing system according to any one of the preceding claims, wherein the venturi tube (24) has an inlet cone (25) of 30-90 degrees.

6. The dispensing system according to any one of the preceding claims, wherein the venturi tube (24) has an outlet cone (27) of 10-40 degrees.

7. The dispensing system according to any one of the preceding claims, wherein the cryogenic dispersion (50) is discharged through the orifice (31) of the nozzle (30) forming a spray cone with an angle of no more than 40 degrees.

8. A dispensing system according to any one of the preceding claims, wherein the liquid phase (11) comprises at least 90 wt.% dimethyl ether.

9. A dispensing system according to any one of claims 1-7, wherein the liquid phase (11) comprises at least 90 wt% of a mixture of dimethyl ether and one or more alkanes selected from propane, n-butane and isobutane.

10. The dispensing system according to any one of the preceding claims, wherein the spray opening (41) of the partition (40) has a minimum diameter of 2-10 mm.

11. The dispensing system according to any one of the preceding claims, wherein the actuatable valve (20) comprises a fixed part (18) fixed to the container and comprising the venturi tube (24) and the liquid inlet (28) and forming a circumferential side wall of the mixing chamber (21), the valve (20) further comprising a movable part (19) movable relative to the fixed part between a valve open position and a valve closed position, the movable part comprising the nozzle (30), wherein the nozzle (30) has a circumferential side wall (16) surrounding a passage for the liquid-in-gas dispersion (50) and a through hole (15) in the side wall, wherein the through hole is arranged such that: in the valve open position, the through hole fluidly connects the mixing chamber (21) and the orifice (31) of the nozzle (30), and in the valve closed position, the movable part and the stationary part together seal a passage between the mixing chamber (21) and the through hole (15).

12. Dispensing system according to claim 11, wherein the stationary part (18) is provided with a gasket (60) through which the movable part (19) extends, wherein the gasket seals the passage between the mixing chamber (21) and the through hole (15) when the movable part is in the valve closed position.

13. The dispensing system according to any one of the preceding claims, wherein the container (10) has a top wall (9) at an end opposite the nozzle (30), the system further comprising a holder (70) for movably holding the container (10) therein, wherein the partition (40) and the nozzle (30) are fixed relative to the holder and the holder surrounds a substantial portion of a circumferential outer wall of the container (10) while leaving the top wall (9) at least partially free to allow a user to actuate the valve (20) relative to the container towards the spray opening by pressing his or her fingers on the top wall (9) of the container.

14. Cosmetic method for treating the skin, comprising the topical application of a cryogenic dispersion onto the skin of a human or animal using a dispensing system (1) according to any one of the preceding claims.

15. The cosmetic method of claim 14, wherein the low temperature dispersion is applied to a wart, a nevus, a freckle, a skin tag, an age spot, or a lentigo.